Mixing devices for mixing polymer and monomer for production of bone cement are already known from U.S. Pat. No. 5,328,262 and U.S. Pat. No. 4,973,168. At the device of U.S. Pat. No. 5,328,262, there is polymer in the mixing container and monomer is poured into the mixing container from a liquid container. Then, polymer and monomer are mixed under a vacuum and after mixing, the bone cement is collected under a vacuum for subsequent discharge. At the device of U.S. Pat. No. 4,973,168, there is polymer in the mixing container and monomer in a syringe with a cannula. This cannula is used for puncturing a membrane in the mixing container, whereafter monomer is injected into the mixing container.
It has been noticed that the device and method of U.S. Pat. No. 4,973,168 for adding monomer to polymer do not meet the present demands for quick and effective distribution of the monomer in the polymer for producing bone cement with the required properties.